1. Field of the Invention
This invention relates to alignment of press blocks, and more especially to alignment of stamper plates mounted on disc record press blocks.
2. Description of the Prior Art
Disc records are typically manufactured from a shot of thermoplastics material, which is inserted between a pair of opposing press blocks in a disc record press, the press blocks each having mould members to which stamper plates are fixed. Closure of the press under suitable temperature and pressure control produces a disc record bearing a positive impression of the corresponding negative impression of an information track imprinted in the stamper plate.
The advent of video disc records has required considerable improvement in quality, necessitating tighter constraint on manufacturing variables and an increased importance in the correct alignment of stamper plates with respect to the axis of rotation of a disc record manufactured therefrom, especially having regard to automatic tracking playback devices.